A cube has an edge length of 4 in. The cube is painted red all over and then cut into 64 cubes of edge length 1 in. How many of these cubes exactly have one fae painted red?

There are four cubelets on each face with one red face, there are 6 faces
so total is 4.6 = 24. All the other cublets have either zero red faces (they are
in the interior of the cube, or have more than one red face as they are from
an edge or corner of the cube.